Machine for regrinding worn crankshafts



July 5, 1949. v. .1. PRINCE MACHINE FOR REGRINDING WORN CRANKSHAFTS '7Sheets-Sheet 1 Filed Dec. 16, 1946 Jufly 5, 1949., v. J. PRINCE MACHINEFOR REGRINDING WORN CRANKSHAFTS 7 Sheets-Sheet 2 Filed Dec. 16, 1946llYl/EJVTOE.

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7 SheetS- -Sheet 5 Filed Dec. 16, 1946 July 5, 1949. v. J. PRINCEMACHINE FOR REGRINDING WORN CRANKSHAFTS 7 Sheets-Sheet 6 Filed Dec. 16,1946 MACHINE FOR REGRINDING WORN CRANKSHAFTS Filed Dec. 16, 1946 7Sheets-Sheet '7 [NVENTOR Vic for J Prince.

ATTORNEY Patented July 5, 1949 UNITED MAQEHNE FOR REGRINDING WORNfiRANKSHAFTS Victor .lolm Prince, Kingston-on-Thames, Englandapplication December 16, 1946, Serial .No. 716,484 In Great BritainApril 22, .1943

Section 1, Public Law 690, August 8, 1946 Patent expires April 22, 19639 Claims.

This invention relates to machines for regrinding worn crankshafts inwhich a grinding wheel is rotated in contact with the periphery of a bigend journal or crankpin, or shaft ends or journals, the work beingmovedwhilst in contact with the grinding wheel so that the Whole of theperiphery of the appropriate part of the work is negotiated. In existingmachines for regrinding crankshafts the grinding wheel, which usually isconsiderably larger in diameter than the work, is mounted to rotate upona fixed aXis so that it is necessary to so set up the work that theactual part, for example crankpin being reground must be rotated on itsown axis. Such a method of setting up is not only tedious and diflicultbut, particularly when grinding a crankpin, the parts of the shaft onits normal axis of rotation, for example, shaft ends and flanges, tendto bias the work, such bias being enhanced by centrifugal force. Also itis necessary to set up the crankshaft for each set of coaxial crankpinsand also it is not possible to make a speedy change from one crankpin toanother.

The main object of this invention is to provide a machine wherein it isunnecessary to set up the work for the grinding of each part.

An important feature of the invention is that instead of mounting thegrinding Wheel axis is fixed bearings, the bearings and consequently thewheel are mounted so as to be capable of swinging movement towards oraway from the work, and means are provided for coupling the wheel axleto the part being worked in such a manner that the work itself in thecase of a crankp-ln will impart a swinging movement to the grindingwheel which results in the periphery of said wheel always beingmaintained a fixed distance from the crankpin axis although the endlesspath generated by the points of contact of the grinding wheel and workis not concentric with the axis of rotation of the work. This ispreferably achieved by coupling the wheel axis to the crankpin by alink, which link has means such as a bifurcated yoke at its end toembrace the pin.

It is to be understood that suitable means for making necessaryadjustments, for example, to close up accurately the grinding wheelperiphcry towards the work axis will be provided.

The accompanying drawings illustrate two preferred forms of machineconstructed in accordance with the invention, both machines beingcapable of grinding :both .main journals and crankpins for one centeringor mounting of the crankshaft.

In the drawings:

Figure 1 is a sectional side elevation of one form,

Figure 2 is a front elevation,

Figure 3 is a view similar to Figure 1 of the second and preferred .formof the invention,

Figure 4 is a front view of the upper part of the machine illustrated inFigure 3,

Figure 5 is a sectional view of the telescopic coupling member used inthe machine illustrated in Figures 3 and 4.

Figure 6 is asectional elevation of a preferred form of tailstockemployed in the machine illustrated in Figures '3 and 4.

Figure '7 is a section on the line -l--l, Figure 6.

Figure 8 is a side view of the grinding wheel trueing attachment.

Figure 9 is a section on the line 9-9, Figure 8, and

Figure 10 is arear view of the attachment looking in the direction ofthe arrow in Figure 8.

Figure 11 is a side view of the :feed screw for the grinding Wheel.

Like reference numerals indicate like or equivalent parts in the twomodifications.

Referring to the drawings, the machine frame I is provided with a benchplate 2 similar to that of a lathe with a headstock 3 at one end and atailstock 4 at the other end with chuck to and rolling centre 5 mountedrelatively ad- J'ustably on a sliding carriage 6 adapted to be traversedon a slide 1 of the plate 2 by a rack 3 and a pinion 9 driven byahandwheel l8. A small horsepower, for example half horsepower threehase electric motor ll, with a suitable reduction gear, drives the chuckshaft via a four speed belt and pulley or other suitable variable speedtransmission device [2.

The grinding wheel is indicated by the reference numeral I3, andadistinctive feature of the invention is that a crankshaft .can be setup normally centred by the chuck 4a and rolling centrei so that it canbe rotated about its normal axis for grinding both its .main journalssupported .truly coaxial with the axis .of rotation of the shaft and itscrankpins or journals occupying their normal throw or radially spacedpositions relatively to the normal axis of the shaft. For this purpose,instead of mounting the grinding wheel shaft M in fixed bearings, suchbearings are housed in the upper ends of two parallel side arms l5constituting the bifurcated upper part of a substantially vertical beaml6 pivoted between its ends by a pivot pin or coaxial lateral lugs l'ljournalled in bearers l8 fixed to the bench plate 2.

The lower end of this oscillatable beam is cranked inverted L fashion asat l9 to accommodate a motor, for example a three horsepower three phaseelectric motor secured to the vertical limb of such cranked part of thebeam by any suitable means such as, for example, a steel band 2|tensioned about the motor housing and anchored to such vertical limb. Bythis means, the grinding wheel aXis can be traversed substantiallyperpendicularly or radially relatively to the chuck axis, this conditionoccurring when the crank pins or journals of the crankshaft are beingground.

When the main journals of the shaft are to be ground the position of thegrinding wheel axis is carefully selected by the operator, but when acrankpin is being ground, the work itself imparts such movement to thegrinding wheel as will ensure the whole perimeter of the appropriatecrankpin being ground properly. although the endless path generated bythe points of contact of the grinding wheel and the work is notconcentric with the axis of rotation of the crankshaft.

The means by which the operator controls and selects the position of thegrinding wheel axis provides for quick and fine adjustments andcomprises a feed screw 22 receiving a nut 23 adapted to be traversedalong the feed screw 22 for quick adjustments by the rotation of a smallhandwheel 24 and a sleeve 25 loose upon the unthreaded end of the feedscrew 22 and rotated by a large handwheel 26 to traverse such sleeveaxially through a split nut 21 supported within a bracket 28 fixed tothe front panel 29 of the machine frame. The sleeve 25 impartstranslative movements to the feed screw 22 through the medium of thrustbearings 30.

The nut 23 on the feed screw 22 is formed with a depending lug 23aguided in a channel 3la of a fixed inclined guide arm or ramp 3|, thelug 23a carrying a roller 23b running upon the base of the said channel.

The beam I6 is readily detachably coupled to this nut 23, and suchconnection is effected by a toggle or latch 32, pivoted at one end tothe lower end of the beam l6, its free end being formed with a dependinglug 3211 which is urged by a torsion spring 33 into a recess 230 of thenut 23. It will be appreciated that when the lug 32a is engaged in thenut 23, translative movement imparted to such nut will transmit angularadjustment to the beam to vary the pressure of the grinding wheelagainst the work, for example for grinding a main journal of acrankshaft.

The grinding wheel shaft l4 and the shaft of the motor 20 are connectedby belts 34 passed over pulleys [4a and 20a respectively on such shaftsso that the grinding wheel is permanently coupled to the motor 20.

The latch 01' toggle 32 is operated by any suitable remote controldevice for disengaging its lug 32a from the nut 23, for example by meansof a Bowden cable 35 connected at one end to the toggle and at the otherend to a handle or treadle, conveniently accessible to the operator.

For grinding a big end journal or crankpin, means is provided tomaintain the work at a correct relative distance from the axis of thegrinding wheel, the beam l6 being disconnected from the nut 23 so thatit is free to oscillate under the control of the work. Such meanscomprises a pair of arms 33 radiating from and supported loosely uponthe grinding wheel shaft by bearings and cranked downwardly as at 36atowards the work substantially in continuity with the periphery of thecustomary guard 31. The free ends of these cranked extensions 35a arefitted with steel parallel guide bars 38 for a steel sliding finger 39which is adjustable translatively selectively to said guide bars by afeed screw 40 operated by a hand wheel 4i supported by a bracket 42joining the free ends of the said cranked extensions 36a of the arms 35.The arms 36 thus form a link connection between the work and the axis ofthe grinding wheel so as to oppose any tendency of the work to vibrateor bounce relatively to the wheel or vice versa. The size to which thecrankpin 44 is to be ground is regulated by the handwheel 4| which canbe manipulated whilst the grinding is in progress as likewise can be thehandwheel 26 for adjusting the grinding wheel relatively to the work.Both of these handwheels can be graduated to afford a rough measurementof the adjustment, the actual measurement of the work being by means ofa hand gauge.

The work, indicated in Figure 1 by broken lines 43 as a crankpin 44 isengaged between the guide bars 38 and the finger 39, the finger 39having an inclined work-engaging lower edge 39a which formssubstantially a V with the lower parts of the guide bars 38 (as shown inFigure 1) to engage wide angle spaced points, for example apart of thework, whilst the lower extremities of the said guide bars are bevelledas at 38a so that they can almost contact with the grinding wheel inclose proximity to the actual grinding zone. The inclination of theworkengaging edges of the guide bars is such as to form an obtuse anglewith the tangent common to the work and grinding wheel, and consequentlyit will be soon by reference to Figure 1 of the drawings that the workis firmly engaged at three points. By such means the work is maintainedin constant effective engagement with the grinding wheel, and thegrinding wheel axis oscillates in conformity with the endless pathgenerated by the point of contact between wheel and work.

A guard plate or deflector 45 is fixed to the beam 6 just above thefulcrum of the beam to deflect metal particles on to the plate 2 whichotherwise might fall down to the motor 20.

Referring now to the form of machine illustrated in Figures 3 and 4, theessential details fol low closely on those illustrated in Figures 1 and2, the machine in Figures 3 and 4 having been designed with a view tosimplified operation, robust and rigid construction and the productionof work with a high degree of accuracy, without employing a highlyskilled operator. Like reference numerals on the same or equivalentparts in the two forms of machine have been used.

From Figures 3 and 4 it will be seen that a rigid control post 46 ismounted on the frame and that the grinding wheel assembly is coupledthereto by means of a telescopic connector 41 later described in detail.This connector allows ii for the easy release of the grinding Wheelassem bly from the control post when it is desired to worl; on acrankpin. The head houses feed screw, the movement of which is ootanedby the two hand wheels 2d and 25, the feed screw receiving a nut whichcarries a ball head 43 projecting from the head. The hand wheel as turnsthe screw directly to cause rotation of the feed screw resulting in foreand aft movement of the ball head it, which movement is transmitted tothe grinding wheel assembly through the connecting member 47 enablingthe operator to move the wheel in relation to the work when grindingmain bearings. The hollow head 58 houses the me by which the operatorcontrols and selects the position of the grinding wheel axis whengrinding main journals, and as shown in Figure 11, said means comprisethe feed screw 22, the movement of which is obtained by the two handwheels 24 and 25, the feed screw 22 -eceiving a nut which carries adepending guide member moving on a slide Riot, which guide carries theball head it projecting through a slot through head ill. The hand wheelturns the feed screw 22 directly to cause rotation of said feedresulting in fore and aft movement of ba l head All, which movement istransmitted to the grinding wheel assembly through the connect-- member4'! enabling the operator to l the wheel in relation to the were whengrin-7b ing main bearings. The wheel it is coupled oy means of a wormdrive, the wheel 2i of which is seen in Figure 11, and thr aded. sleevearound a fine threaded A art on the feed "'"w so that a fine adjustmentobtained. Tie actual quick and fine adjusting mechanism followsconventional practice. The turning of the wheel 2% results in axialmovement of the screw 22.

However, the hand v e1 25 may move with respect to a suitably calibratedsce on a fixed part around its periph. so that the operator work to finelimits with the iinimun'l use oi amicroineter. For instan teramicrometer check it is necessary to remove .001. inch from a mainbearing, this can be do by the use of the fine adjustment scale, the lrometer being used only for the final check.

It will be seen that the motor Eli is carried by the beam it below theswim u ii and serves to counterbalance the grinding wheel, whilst thegrinding wheel assembly is held rigidly on the upper part of the controlpest, resulting in an extremely rigid construction.

Figure 5 is a sectional view of the telescopic conning member. Thisccmpri s an inner rod member Evil having a o part 55, the one end of therod being cou d to a hollow memher 52 in which the ball til received.The rod Ell telescopes in the sleeve 53 and is prevented from rotationby the screw wit n the spline 55 in the rod The sleeve has a pair offlanges one of which shown in the drawing, and between these flanges twofinger triggers El, 5% are mounted, the lingers of which (tie and 5%respectively) project into housings within the sleeve end. The fingersurged apart by the coil spring 558.

Secured to the grinding wheel guard is a projecting ball head and thegrinding wheel sembly is released m the control post merely by squeezinghe tr and stock 65, there-- by releasing the ball. he other trigger 5'.allows for a coarse adjustment of the position of the grinding wheel onits Pivoted to the said trigger 51 is a link 62, the other end of whichcarries a wedge member 63, co-operating with an inclined plane 64, theupper surface of the wedge carrying the serrated faced block 65, whichmates with the rack 5|. The upper end of the finger 51a, is notched sothat when the trigger 51 and stock Bl are squeezed the said triggerfulcrums about the notch. This retracts the link allowing the block todrop so that the sleeve 53 can now move axially with respect to the rod.

The above arrangement provides a very ready and rigid engage and releasecoupling between the grinding wheel assembly and the control post.Moreover, it allows for rapid initial adjustment of the grinding wheel.periphery with respect to the work when grinding main bearings.

Referring now to Figures 6 and 7, there is illustrated in front and sidesection respectively a preferred and novel form of tailstoclz. The tailstock illustrated is controlled by a single lever which serves the dualpurpose of clamping or releasing the tailstock on the bed, and ofapplying load to the rolling centre when the work is set up. The load isof importance when grinding crankshafts, and the actual load isdetermined by the design of the tailstock and is not left to the skillof the operator.

The main casting or hollow housing 66 is shaped to embrace at its bottomthe slide 7. Pivoting on the bar or lever 61 is the locking member 68,which member has a nose part 69 beneath which engages one end of thelever El rockable on the cross bar H. The operating lever 12 is pivotedon a cross pin 73 and has a cam it thereon which cam is formed tocontact with both levers ii? and 15. The operating lever '12 extendsthrough a slot in the housing 66. The lever 15 is justable by means ofthe bolt and socket pivot arrangement 76, and the upper end of saidlever l5 engages within a slot ii in the centre sleeve 18. This centresleeve is urged forwardly means of the spring it.

In using the tailstock, the operator raises the hand lever '12 and thisfirstl Y pivots the lever .15 so that the centre sleeve is moved axiallyagainst the spring to release the work. Further upward movement of thelever 52 releases the tailstocl'. on its slide. Downward movementfirstly locks the tailstock to the bed, and then releases the springwhich moves the centre sleeve forwe Thus, by a simple operation, withoutthe use of spanners or other tools, the tailstocl; can moved toposition, and the load on the work is always constant as determined bythe spring 79.

It will be appreciated that with either of the modifications it is necesy for the wheel face to be trued up accuro and for plane of the surfaceto be dec parallel with the oi the grinding wheel. h a wheel trueingdevice is indicated generally .Lll Figure 3 by the ref-- erence numeral10 and its essential constructional features are shown in Figures 8, 9and 10. The device consists of a diamond dd mounted in a carrier 8!which carrier can be moved axially by the knurled nut Turning with thenut is a notched bush 83, and spring pressed plunger 84 contactstherewith. The arrangement is such. that for each movement of theplunger from one notch to the next, the diamond is advanced or retardeda fixed part c. 0.001 part of an inch. The assembly is shaped to bemounted in the dovetail slideway and is coupled to nut member at, whichis threaded the screw rod E7, which rod is turned. by the hand wheel 35.

When it is necessary to true up the grinding wheel, the hand wheel 88 isrotated to bring the diamond carrier and assembly to the limit in onedirection and the knurled nut moved so that the diamond is advanced onestep. Then with the grinding wheel rotating, the hand wheel 88 is turnedso that the diamond slowly traverses the grinding surface.

It will be understood that the initial setting up of the wheel trueingdevice must be undertaken so that this traversing movement maintains thediamond dead parallel with the grinding wheel axis. To achieve this, awedge plate 89 is mounted between the attachment and the grinding wheelcover, said plate having arcuate slots 99 therethrough, through whichpass the bolts 95, which serve to secure the attachment to the cover. Itwill be seen that by loosening off the bolts 8! and rotating the plate69 slightly, and then tightening the bolts, the linear path of travelwith respect to the axis of the grinding wheel can be altered. Thisadjustment is intended for initial setting, as when the path has beenaccurately adjusted, with normal use no further setting will benecessary.

Instead of using a variable speed transmission device employing a beltand pulley arrangement as shown in Figure 2, a device of known formhaving a hand control lever l2a moving through an arc as shown in Figure4 may be used, the speed being infinitely variable between maximum andminimum speeds.

I claim:

1. A machine for grinding and regrinding crankshafts comprising amachine frame and bed, means to support the work for rotation about itsnormal axis of rotation, a grinding wheel mounted on a beam above themachine bed, said beam being mounted to swing towards or away from thework, adjustable and detachable coupling means for connecting the beamto a fixed part of the machine, said coupling means connecting thegrinding wheel beam to a nut, a manually controlled rotatable feed screwto traverse said nut, supporting means for said feed screw to allowaxial movement of said screw, and a second feed screw device to movesaid nut traversing feed screw axially and crankpin engaging meanscarried by the swinging beam, which crankpin engaging means areadjustable to different diameters and throws of crankpins and serve tomaintain the work pressed against the grinding wheel for completerotation of the crankshaft.

2. A machine for grinding and regrinding crankshafts comprising amachine frame and bed, means to support the work for rotation about itsnormal axis of rotation, a grinding wheel mounted on a beam above themachine bed, said beam being mounted to swing towards or away from thework, a rigid control post upstanding from the machine bed and adjacentthe grinding wheel assembly, with means to couple the said assembly to,or release same from, the post or support and a manually controlled feedscrew device associated with the post or support and connected to thecoupling means, which feed screw serves to effect the adjustment of theposition of the grinding wheel axis and crankpin engaging means carriedby the swinging beam, which crankpin engaging means are adjustable todifferent diameters and throws of crankpins and serve to maintain thework pressed against the grinding wheel for complete rotation of thecrankshaft.

3. A machine for grinding and regrinding crankshafts comprising amachine frame and bed, means to support the work for rotation about itsnormal axis of rotation, a grinding wheel mounted on a beam above themachine bed, said beam being mounted to swing towards or away from thework, a rigid control post upstanding from the machine bed and adjacentthe grinding wheel assembly, with means to couple the said assembly to,or release same from, the post or support, said coupling meanscomprising a telescoping member having means for quickly releasing itsone end from either the post or the grind-- ing wheel assembly andmanually controlled means whereby the overall length of the said membercan be varied to provide a rapid means for setting up initially thegrinding wheel with respect to the work surface when grinding mainjournals, and a manually controlled feed screw device associated withthe post or support and connected to the coupling means, which feedscrew serves to effect the adjustment of the position of the grindingwheel axis.

4. In a machine for grinding and regrinding crankshafts, the combinationcomprising a frame, means carried by said frame to support the work forrotation about its normal axis both for grinding main journalsconcentric with said axis and for crank journals having their normalthrow whilst being ground, a grinding wheel, means for mounting saidwheel swingably carried by said frame, means for driving said wheel andurging said wheel mounting means to vertical position, and meansadjustable along a fixed axis and connectible to said wheel mountingmeans for holding same in a predetermined position.

5. In a machine for grinding and regrinding crankshafts, the combinationcomprising a frame, means carried by said frame to support the work forrotation about its normal axis both for grinding main journalsconcentric with said axis and for crank journals having their normalthrow whilst being ground, a grinding wheel, means for mounting saidwheel swingably carried by said frame, means for driving said wheel andurging said wheel mounting means to vertical position, means mounted forlimited rotation on the shaft of said. wheel for holding a crank journaladjacent said wheel, and adjustable means connectible to said wheelmounting means for holding same in a predetermined position.

6. In a machine for grinding and regrinding crankshafts, the combinationcomprising a frame, means carried by said frame to support the work forrotation about its normal axis both for grinding main journalsconcentric with said axis and for crank journals having their normalthrow whilst being ground, a grinding wheel, means for mounting saidwheel swingably carried by said frame, means for driving said wheel andurging said wheel mounting means to vertical position, means mounted forlimited rotation on the shaft of said wheel for holding crank journalsof different diameters adjacent said Wheel, and adjustable meansconnectible to said wheel mounting means for holding same in apredetermined position.

7. In a machine for grinding and regrinding crankshafts, the combinationcomprising a frame, means carried by said frame to support the work forrotation about its normal axis both for grinding main journalsconcentric with said aixs and for crank journals having their normalthrow whilst being ground, a grinding wheel,

' means for mounting said wheel swingably carried by said frame, meansfor driving said wheel and urging said wheel mounting means to verticalposition, means mounted for limited rotation on the shaft of said wheelfor holding crank journals of different diameters adjacent said wheel,said crank journal holding means including guidingly related adjustablejaws engaging a crank journal, and adjustable means connectible to saidwheel mounting means for holding same in a predetermined position.

8. In a machine for grinding and regrinding crankshafts, the combinationcomprising a frame, means carried by said frame to support the work forrotation about its normal axis both for grinding main journalsconcentric with said axis and for crank journals havin their normalthrow whilst being ground, a grinding wheel, means for mounting saidwheel swingably carried by said frame, means for driving said wheel andurging said wheel mounting means to vertical position, means mounted forlimited rotation on the shaft of said wheel for holding crank journalsof different diameters and throws adjacent said wheel, and adjustablemeans connectible to said wheel mounting means for holding same in apredetermined position.

9. In a machine for grinding and regrinding 10 crankshafts, thecombination comprising a frame, means carried by said frame to supportthe work for rotation about its normal axis both for grinding mainjournals concentric with said axis and for crank journals having theirnormal throw whilst being ground, a grinding wheel, means for mountingsaid wheel swingably carried by said frame, means for driving said wheeland urging said wheel mounting means to vertical position, meansadjustable along a fixed axis and connectible to said wheel mountingmeans for holding same in a predetermined position, and means forconnecting said wheel mounting means to said adjustable holding means.

VICTOR JOHN PRINCE.

REFERENCES CITED The following referenlces are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 1,833,602 Batterman et a1. Nov.24, 1931 1,871,504 Einstein et a1. Aug. 16, 1932 2,071,882 Kremer Feb.23, 1937 2,340,602 Leusch Feb. 1, 1944 2,349,108 Myers May 16, 1944

